Pigments are often used in cosmetic compositions to hide imperfections in the skin, in particular skin discolorations. For hyperpigmentation, redness and shadows, pigments which can cover or lighten the appearance of skin are typically used. However, the use of pigments in cosmetic compositions can produce other aesthetic deficiencies. Each person's skin has certain angular reflectance and color space properties. These properties can change significantly in skin coated with a pigmented film or lightening composition and the result will appear unnatural. For example, pigments which provide a lighter appearance of the skin can also produce an ashy appearance on darker skin tones, which correlates with increasing angular dependence. Skin naturally has a close to Lambertian or flat reflection profile at incident angle of <60°.
Compositions that obscure blemishes by reflecting light away from them are known in the art. For example, compositions containing platelets of alumina treated with metal oxides and spherical scattering components comprised of silica coated with titanium dioxide are described in U.S. Pat. No. 6,511,672, which states that both components have intense reflection properties, rendering these pigments unsuitable for daytime wear if used alone because the intense reflection appears to enhance wrinkles and lines. Alternatively, pigment particles that have been coated with networks of smaller particles that have higher refractive indices can achieve a transparency that makes the skin look natural while hiding blemishes, as in U.S. Pat. No. 7,531,184. These compositions commonly employ titanium dioxide, which can produce an appearance of the skin that is too pearlescent or too chalky.
Titanium dioxide has often been mentioned in the art as causing cosmetic compositions to appear too white, powdery or chalky on skin. Fine particles of titanium dioxide are hard to disperse in cosmetic compositions and often form large aggregates. However, titanium dioxide particles having a larger size often become conspicuous in cosmetic compositions. European Patent No. 0801941 describes certain sunscreen compositions which employ spindle-shaped titanium dioxide rather than spherical shaped titanium dioxide to enhance the dispersion of the compound in the composition. It is stated in this patent that if the length or diameter of the spindle-shaped titanium becomes too long, the transparency in the visible light is detracted from, the finish of the sunscreen is diminished and the appearance of the skin becomes too white. Spindle- or needle-shaped titanium dioxide particles are also used in the cosmetic compositions of Japanese Patent Publication No. 11-035441, Japanese Patent No. 288084, Japanese Patent Publication No. 10-291922, Japanese Patent Publication No. 08-048614, and U.S. Pat. No. 5,763,497.
The need exists for alternative methods to lighten the appearance of skin, or to hide imperfections while maintaining a natural appearance of skin, which overcomes the problems associated with previous methods and compositions and which would represent a significant advance in cosmetic art.
The present invention provides methods for imparting a pigmented film by topical application of a cosmetic composition comprising certain fibrous pigments and coloring agents which are characterized in that the appearance of the skin is close to natural skin.
The present invention also provides methods for imparting a lightening appearance of skin by topical application of a cosmetic composition comprising certain fibrous pigments. None of the existing art provides the advantages and benefits of the present invention.
It is an object of the present invention to provide compositions comprising fibrous pigments that improve the appearance of skin while maintaining a reflection profile of the skin coated with the composition that is similar to natural skin.
It is another object of the present invention to provide compositions comprising fibrous pigments that improve the appearance of skin while maintaining color space values of the skin coated with the composition that are similar to natural skin.